As a semiconductor encapsulating material, the flame-retardancy of an epoxy resin composition must achieve UL-94V-0 level of the quality standard for flame-retardance. In the prior art, in order to achieve this quality standard, the main method is adding a certain amount of a flame retardant. There are multiple flame retardants being used presently, and traditionally (non-environmentally), bromine flame retardants and antimony flame retardants are mainly used. However, along with the strengthening of global environmental awareness, various countries proposed Environmental Protection Act in succession, restricting the use of bromide-containing flame retardants and hazardous substances containing lead and so on in electronic products. In early 90s of last century, countries such as America, European countries and Japan etc. realized that, with the rapid development of electronic industry, the hazards of the wastes of industrial products, particularly the lead in lead-tin solders which are annually consumed in large amounts, must be devoted much attention. Presently, China has been one of the major exporters of household appliances in the world; Chinese electronic products, if entering into the international market, would be subjected to the restrictions of limiting laws such as ROHS etc. with the limitation to hazardous substances in electronic products. According to the requirements of the “Restriction of Hazardous Substances” issued by the European Parliament and Council, commercially available electronic information products within the national key regulatory directory may not contain hazardous substances such as lead, antimony, mercury, cadmium, hexavalent chromium, polybrominated biphenyl (PBB) or polybrominated diphenyl ether (PBDE) etc. in China since Jul. 1, 2006. Therefore, the traditional bromine flame retardants and antimony flame retardants will be gradually replaced by an environment-friendly flame retardant, whereas the flame-retardant effect of presently used environment-friendly flame retardants cannot compete with the performance of Br/Sb flame retardants, which need to be added in a larger amount to achieve the flame-retardant requirement. However, the use of such large amount of a flame retardant will seriously affect the flow properties, molding properties and reliability of an epoxy resin composition.
In semiconductor encapsulation, the transition of high temperature reflux process of traditional lead-containing solder at 240° C. to high temperature reflux process of green, environmentally friendly, lead-free solder at 260° C. puts forward higher demands for the reliability of an epoxy molding compound. Above all, in the encapsulation of a green, environmentally friendly, Quad Flat Non-lead Package (QFN), the epoxy molding compound must satisfy the requirements of the high temperature reflux in the lead-free encapsulating process on reliability, should have properties such as high heat resistance, high adhesion, as well as low water absorption and low stress etc., so as to reduce or avoid the demixing phenomenon between the epoxy molding compound and chip/paddle/framework after the high temperature reflux. Secondly, the epoxy molding compound must further have a lower thermal expansion coefficient, which is matched with the thermal expansion coefficients of the semiconductive encapsulating materials such as chip/paddle/framework etc., to reduce the package warpage phenomenon due to the mismatch of thermal expansion coefficients. Therefore, in QFN encapsulation, an epoxy molding compound must have high reliability and low warpage properties to reduce or avoid undesirable phenomena such as inner demixing and outer warpage of a semiconductor package, etc.